Lignocellulose-degrading enzymes, free-radical transformations during composting of lignocellulosic waste and biothermal phases in small-scale reactors
“…Endoglucanase-type cellulase activity in compost II (PSSF), containing less accessible lignocellulose fraction, was significantly higher only at the end of the composting period (phases 5 and 6). This effect coincided with a significant increase in ligninase activity, as described in my earlier work (Bohacz 2017). The convergence of maxima of cellulo- and ligninolytic activities in compost II indicated progressive degradation of the ligninocellulose complex.Fig.…”
Section: Resultssupporting
confidence: 85%
“…Barrena et al ( 2008 ) also mentioned respiratory activity and dehydrogenase activity as indicators of microbiological activity of the composting process. Bohacz ( 2017 ) described the dynamics of changes in ligninolytic enzyme activities, such as ligninases (LiP), HR peroxidase (HRP), and ligninolysis auxiliary enzymes, such as glucose oxidase (GOD) in successive biothermal phases in composts containing pine bark, sawdust, grass, straw, and chicken feathers.…”
The aim of this study was to show the dynamics of changes in the activity of enzymes responsible for C, N, and S metabolism, i.e., cellulase, protease, urease, and arylsulfatase in two lignocellulosic composts as well as changes in the concentration of mineral forms important in plant nutrition (N-NH
4
+
, N-NO
3
−
, S-SO
4
2−
). Most of the enzyme activity was higher during 10 weeks of composting in compost I, containing higher amounts of easily available organic matter than in compost II. Enzymatic activities in compost II remained at a higher level for a longer time, but they increased at a slower rate. Mineral content changes in the compost mass consisted primarily of an increase in N-NO
3
−
concentration and a decrease in N-NH
4
+
and S-SO
4
2−
levels, especially in compost I. The concentration of mineral nitrogen and sulfur forms in compost water extracts was about 10–100 times lower than in the compost mass. At the end of composting, the amount of sulfates in the compost mass was 30 and 150 mg kg
−1
dw in compost II and I, respectively. In this context, the composts obtained should be considered valuable for fertilizing soils poor in this component and for cultivating plants with high sulfate S demand.
“…Endoglucanase-type cellulase activity in compost II (PSSF), containing less accessible lignocellulose fraction, was significantly higher only at the end of the composting period (phases 5 and 6). This effect coincided with a significant increase in ligninase activity, as described in my earlier work (Bohacz 2017). The convergence of maxima of cellulo- and ligninolytic activities in compost II indicated progressive degradation of the ligninocellulose complex.Fig.…”
Section: Resultssupporting
confidence: 85%
“…Barrena et al ( 2008 ) also mentioned respiratory activity and dehydrogenase activity as indicators of microbiological activity of the composting process. Bohacz ( 2017 ) described the dynamics of changes in ligninolytic enzyme activities, such as ligninases (LiP), HR peroxidase (HRP), and ligninolysis auxiliary enzymes, such as glucose oxidase (GOD) in successive biothermal phases in composts containing pine bark, sawdust, grass, straw, and chicken feathers.…”
The aim of this study was to show the dynamics of changes in the activity of enzymes responsible for C, N, and S metabolism, i.e., cellulase, protease, urease, and arylsulfatase in two lignocellulosic composts as well as changes in the concentration of mineral forms important in plant nutrition (N-NH
4
+
, N-NO
3
−
, S-SO
4
2−
). Most of the enzyme activity was higher during 10 weeks of composting in compost I, containing higher amounts of easily available organic matter than in compost II. Enzymatic activities in compost II remained at a higher level for a longer time, but they increased at a slower rate. Mineral content changes in the compost mass consisted primarily of an increase in N-NO
3
−
concentration and a decrease in N-NH
4
+
and S-SO
4
2−
levels, especially in compost I. The concentration of mineral nitrogen and sulfur forms in compost water extracts was about 10–100 times lower than in the compost mass. At the end of composting, the amount of sulfates in the compost mass was 30 and 150 mg kg
−1
dw in compost II and I, respectively. In this context, the composts obtained should be considered valuable for fertilizing soils poor in this component and for cultivating plants with high sulfate S demand.
“…The loading plot shows the influence of the variables (endoxylanase, b-xylosidase and proteolytic activities) on fungal isolates and displays the correlation structure of the variables. Two plots help to analyse the correlation between the observations and the variables (Bohacz, 2017). The statistical analysis of the main components on the enzyme production by Aspergillus fungi showed that the first principal component (PC1) was responsible for explaining 45.1% of the results' variability, and the second main component (PC2) was responsible for 26.9% variation, resulting in 72% of total variation of the experimental results.…”
Section: General Trends In the Enzymatic Activity In Individual Aspermentioning
Xylanases hydrolyse efficiently the xylan component of hemicelluloses into single xylose monomers. Hence, these enzymes are suitable to be applied in the bioconversion of lignocellulosic wastes such as sugarcane bagasse to improve the bioethanol process. Misiones rainforest in the northeast of Argentina has a huge biodiversity which becomes the most likely site to screen new fungal isolates for powerful xylanolytic enzymes. The aim of this work was to find efficient xylanolytic Aspergillus with low levels of proteolytic enzymes through the isolation and exploration of native fungi from Misiones. Fungi were isolated from different locations of this subtropical region and 25 Aspergillus isolates were screened based on their ability to produce xylanolytic and proteolytic enzymes. From the principal component and conglomerate analysis, six groups were discriminated. The most promising fungi presented the highest endoxylanase and b-xylosidase activities and the lowest proteolytic activities. These isolates were A. niger LBM 055 and A. niger LBM 134 which reached 29 and 27 UmL À1 of endoxylanases, respectively; 0.6 UmL À1 of b-xylosidases, no casein and very little gelatin proteases. This study proves that the search of new fungi from nature is an important strategy to find novel isolates with the ability to secrete high-performance xylanases and exploit these enzymes in the bioconversion of lignocellulosic wastes.
“…Additionally, after composting was completed, the sum of alkaline cations were determined using the Kappen method and the sorption capacity of composts (CEC) was calculated from the total hydrolytic acidity values and the sum of alkaline cations. After the completion of the composting process, the E 4 /E 6 value was also determined, i.e., the ratio of absorbance at 465 and 665 nm for humic acids, as described in the previous work of Bohacz [25]. The C/N ratio in both composts was calculated at the end of the composting period, i.e., at month 7.…”
Section: Chemical Properties Of Solid Compost Fractionsmentioning
Purpose Lignocellulosic biomass waste is produced in large quantities and only a small part is used for utility purposes. The aim of the work was to assess the fertilization value of the solid fraction and water extract of lignocellulosic composts. Methods Compost I contained 42.86% pine bark, 34.28% grass, 20.0% sawdust and 2.86% chicken feathers; compost II contained 25.54% pine bark, 10.63% wheat straw, 51.07% sawdust and 12.76% chicken feathers. Seldom described physical properties and phytosanitary and sanitary status of composts as well as macro-and micronutrients and heavy metals concentrations were determined in the solid fraction and water extracts of composts and their impact on the germination of Lepidium sativum L. using PC analysis. Results Composts were characterized by good physical properties and a light product, safe phytosanitary status, which was related to the prevalence of potentially antagonistic fungi, especially in compost II. The frequency of Aspergillus fumigatus, considered an opportunistic human pathogen, decreased during the composting. Heavy metal concentrations did not exceed permissible values for improvers and cultivation media in the solid and aqueous compost fractions. The tested composts were sanitary safe. Both composts were non-toxic to plants, because the germination index in compost I was PCA analysis demonstrated that the majority of micro-and macronutrients and heavy metals had a significantly negative effect on root elongation and germination of the test plant (cress) seeds, especially in compost I. Conclusions Lignocellulosic waste after composting is a valuable and safe organic fertilizer.
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